Social Support. Physiological Processes, and Health

Social relationships serve important functions in people's everyday lives. Epidemiological research indicates that supportive relationships may also significantly protect individuals from various causes of mortality, including cardiovascular disease. An important issue is how social support influences such long-term health outcomes. In this article, we review evidence indicating that social support may influence mortality via changes in the cardiovascular, endocrine, and immune systems. These data suggest that it may be worthwhile to incorporate social-support interventions in the prevention and treatment of physical health problems.     

Necessary condition for forward progression in ballistic walking

Ballistic walking requires an appropriate configuration of posture and velocity at toe-off to avoid backward falling. In this study, we investigated a determinant of the state of the body center of mass (COM) at the toe-off with regard to ballistic walking. We used an inverted pendulum model to represent ballistic trajectories and the necessary condition for forward progression by a simple relationship between the COM states (position and velocity) at toe-off. This condition was validated through a computer simulation of a 7-link musculoskeletal model and measurement experiments of human movements involving stepping and walking. The results of the model simulation were in good agreement with some of the results predicted by the inverted pendulum model. The measurement experiments of walking and stepping movements showed that most COM states at toe-off satisfied the condition for forward progression and the measured trajectories during single support phase were similar to the ballistic trajectories although humans are capable of walking in non-ballistic ways. These results suggested that the necessary condition for forward progression can predict the COM states at toe-off for efficient movement and for avoiding backward falling during single support phase.     

Motion impressions enhanced by converging motion lines

We investigated how motion lines drawn in the background of a running human silhouette affect motion impressions of a runner in a static image. Observers evaluated the strength and direction of motion impression. The results show that parallel lines do not enhance frontoparallel motion impressions, while converging lines do so in an in-depth direction. This is a counter-example to the hypothesis that motion lines in the background represent motion streaks of the background when one visually tracks a moving object.